The GM Ecotec engine, also known by its codename L850, is a family of all-aluminium inline-four engines, displacing between 1.4 and 2.5 litres. Confusingly, the Ecotec name was also applied to both the Buick V6 Engine when used in Holden Vehicles, as well as the final DOHC derivatives of the previous GM Family II engine; the architecture was substantially re-engineered for this new Ecotec application produced since 2000. This engine family replaced the GM Family II engine, the GM 122 engine, the Saab H engine, and the Quad 4 engine. It is manufactured in multiple locations, to include Spring Hill Manufacturing, in Spring Hill, Tennessee, with engine blocks and cylinder heads cast at Saginaw Metal Casting Operations in Saginaw, Michigan.

The Family II is a straight-4 piston engine that was originally developed by Opel in the 1970s, debuting in 1981. Available in a wide range of cubic capacities ranging from 1598 to 2405 cc, it simultaneously replaced the Opel CIH and Vauxhall Slant-4 engines, and was GM Europe's core mid-sized powerplant design for much of the 1980s, and provided the basis for the later Ecotec series of engines in the 1990s.